Back brush



FIG. 1 is a side elevational view of a back brush showing my new design, the opposite side being a mirror image;

FIG. 2 is a bottom plan view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a rear end elevational view thereof; and,

FIG. 5 is a front end elevational view thereof. 

The ornamental design of a back brush, as shown and described. 